Reconstruction of the spatial patterns of desert/loess boundary belt in North China during the Holocene

The desert/loess boundary belt is the transitional region between desert an d loess, where aeolian sand and loess interlock in space and alternate in t ime. It, being seriously unstable in space-time, sensitive to climatic chan ges and with fragile ecological environment, is an ideal region for studyin g the global climate change. There are depositional sequences of paleosol w ith sub-horizontal interbedded aeolian sand and loess, and the stratigraphi cal evidences show that there widely exist 3-4 layers paleosol in sand land s of northeastern China, 4-5 layers in Mu Us Sandy Land and Hunshandake San dy Land, more than 4 layers in the Qinghai Lake region and the Gonghe Basin of Qinghai Province during the Holocene. These indicate that the desert ha s experienced several times of extending and compacting, along with which t he desert/loess boundary belt vibrated. It possesses good coherence with gl obal climate change and eustasy. The coherence shows that the monsoon chang e in East Asia is the primary driving factor for the swing of desert/loess boundary belt. Besides, human influence constantly intensified the swing of the belt, especially in the south of Mu Us Sandy Land during the 2000-3000 aBP.